Xorg segfault on external display plug/unplug

[SilverFire]

Lenovo Thinkpad E540, Ubuntu 15.10, xorg 1:7.7+7ubuntu4, driver NVIDIA 352.63 (also reproduces with NVIDIA 340.96 and nouveau)

When I plug/unplug external display (VGA or HDMI), X server crashes with the following backtrace:

[ 115.212] (II) XKB: reuse xkmfile /var/lib/xkb/server-B20D7FC79C7F597315E3E501AEF10E0D866E8E92.xkm
[ 116.571] (EE)
[ 116.571] (EE) Backtrace:
[ 116.571] (EE) 0: /usr/bin/X (xorg_backtrace+0x4e) [0x564e760ab68e]
[ 116.571] (EE) 1: /usr/bin/X (0x564e75ef7000+0x1b89f9) [0x564e760af9f9]
[ 116.571] (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f1d7f12b000+0x352f0) [0x7f1d7f1602f0]
[ 116.571] (EE) 3: /usr/bin/X (DamageRegister+0x11) [0x564e760323e1]
[ 116.571] (EE) 4: /usr/bin/X (0x564e75ef7000+0xd9b08) [0x564e75fd0b08]
[ 116.571] (EE) 5: /usr/bin/X (BlockHandler+0x8a) [0x564e75f53cca]
[ 116.572] (EE) 6: /usr/bin/X (WaitForSomething+0x163) [0x564e760a83f3]
[ 116.572] (EE) 7: /usr/bin/X (0x564e75ef7000+0x57fa1) [0x564e75f4efa1]
[ 116.572] (EE) 8: /usr/bin/X (0x564e75ef7000+0x5c34b) [0x564e75f5334b]
[ 116.572] (EE) 9: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf0) [0x7f1d7f14ba40]
[ 116.572] (EE) 10: /usr/bin/X (_start+0x29) [0x564e75f3d6c9]
[ 116.572] (EE)
[ 116.572] (EE) Segmentation fault at address 0x10
[ 116.572] (EE)
Fatal server error:
[ 116.572] (EE) Caught signal 11 (Segmentation fault). Server aborting

Expected - not to crash.

The problem occurred after update from 15.04 to 15.10

[SilverFire (d-naumenko-a)]

Please, close this. Accidentally posted without xorg debug files.
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1519279